Fig. 8. The amount of [³²P]ATP bound to live cells was reduced dramatically by including a 50-fold excess of either ß,-methylene ATP (met-ATP) or PPNDS (pyridoxal-phosphate naphthylazo-nitro-disulfate) in the binding assay. The control column represents the amount of [³²P]ATP bound in the absence of any extra added ligand, and each of the other columns is normalized to those counts. Each point represents the mean + S.D. of three trials.